The prior art has used alumina or silica alumina gels as matrix for exchanged zeolites of the faujasite type as, for an example, in U.S. Pat. Nos. 3,140,249, 3,449,265, 3,542,670, 3,557,024, 3,609,103, and 3,558,476. The Filtrol Corporation has for many years sold catalysts composed of rare earth exchange zeolites mixed with alumina and clay produced by spray drying a slurry of the zeolite, hydrated alumina and clay. The clay may be either acid treated halloysite or, ball clay, or other kaolins, or mixtures thereof.
The art of formulation of catalysts composed of zeolites, alumina and clay is well known to those skilled in the art.
Reference may be had to applications Ser. No. 696,889, filed June 17, 1976 now U.S. Pat. No. 4,086,187 and Ser. No. 514,567, filed Oct. 15, 1974 now U.S. Pat. No. 4,010,116 for further description of such catalysts and for improvements therein disclosed and claimed therein.